Proviral insertion into chromosomal DNA is associated with mutation at the site of integration. In systems in which particular mutations can be selected, retroviruses can be used to clone specific cellular genes through the cloning of provirus-cellular DNA junction fragments. With Dr. Cindy Edwards in the Laboratory of Developmental Pharmacology, we are attempting to identify cells in which a Friend murine leukemia provirus has inserted into the gene for the aryl hydroxylase receptor. We plan to use these cells to clone the gene for this receptor. With Dr. David Hoggan (LMM) we are screening cells from humans heterozygous for various autosomal recessive cancer genes to see if amphotropic or xenotropic viruses can be used to identify these genes molecularly. Significance: These experiments provide a novel strategy for identifying and cloning genes involved in the metabolism of aryl hydrocarbons and in a variety of human malignancies.